JP2675459B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a compressor for supplying high pressure gas refrigerant to an evaporator to defrost the evaporator and supplying a liquid refrigerant to a low pressure side inside the compressor by a liquid injection circuit. The present invention relates to a refrigerating device for cooling.

[0002]

2. Description of the Related Art Conventionally, in a freezing / refrigerating showcase installed as a food freezing / refrigerating facility in a supermarket or the like, a high pressure gas refrigerant discharged from a compressor is used for defrosting an evaporator constituting a refrigerating apparatus. In addition, a so-called liquid injection method in which a liquid refrigerant is supplied to the inside of the compressor and evaporated there to cool the compressor is adopted for the purpose of suppressing a rise in the discharge gas temperature of the compressor.

3 to 5 show refrigerant circuit diagrams of a conventional refrigerating apparatus of this kind. Fig. 3 is a refrigeration system of a type in which the refrigerant is condensed by air cooling and the high-pressure gas refrigerant discharged from the compressor is directly flown to the evaporator at the time of defrosting. A refrigeration system of a type in which the high-pressure gas refrigerant discharged from the compressor is directly passed to the evaporator, FIG.
Shows a refrigerating apparatus of a system in which the refrigerant is condensed by air cooling and the gas-liquid mixed refrigerant discharged from the condenser at the time of defrosting is caused to flow to the evaporator. In addition, the same reference numerals are used in the drawings.

First, in FIG. 3, a discharge side pipe 2 is connected to a refrigerant discharge side 1D of a compressor 1 constituted by a scroll compressor or a semi-hermetic compressor, and this discharge side pipe 2 is a refrigerant of an air-cooled condenser 3. It is connected to the entrance side 3A. An outlet side pipe 4 is connected to the refrigerant outlet side 3B of the condenser 3, and the outlet side pipe 4 is connected to the refrigerant inlet side 5A of the receiver tank 5. Receiver tank 5
A dryer 7, a sight glass 8, a valve 9, and solenoid valves 10 and 11 are connected in series to the outlet side pipe 6 connected to the refrigerant outlet side 5B of the expansion valve 12
Is connected to the evaporator 13 via.

The evaporator 13 is installed in the cold air passage of the inner layer of the freezing / refrigerating showcase, and its outlet side is the solenoid valve 1
It is connected to the accumulator 16 from the low-pressure side pipe 15 via 4. A solenoid valve 18 is interposed in a bypass pipe 17 that bypasses the solenoid valve 11 and the expansion valve 12.
The pipe 19 branched from between the expansion valve 12 and the expansion valve 12 is connected to the evaporator 22 via the electromagnetic valve 20 and the expansion valve 21. The evaporator 22 is installed in the outer layer cold air passage of the freezing / refrigerating showcase, and its outlet side is connected to the low-pressure side pipe 15. The pipe 24 branched from between the evaporator 13 and the solenoid valve 14 is connected to the inlet side of the solenoid valve 20 via a check valve 25. Further, the suction side pipe 26 connected to the outlet side of the accumulator 16 is connected to the suction side 1S of the compressor 1.

A liquid injection circuit 27 branches from the outlet side pipe 6 of the receiver tank 5 and is connected to a low-pressure side liquid injection inlet 1R inside the compressor 1 via a capillary tube 28 and a solenoid valve 29. The defrosting pipe 30 branched from the discharge side pipe 2 of the compressor 1 is connected to the outlet side of the solenoid valve 10 via a solenoid valve 31, and the pipe 32 is also branched from the discharge side pipe 2. Is connected to the low pressure side pipe 15 via a solenoid valve 33 and a low pressure adjusting valve 34.

The operation of the refrigerating apparatus shown in FIG. 3 will be described. During normal cooling operation by the evaporator 13, the solenoid valves 10 and 1 are operated.
1, 14 and 29 are open and the other solenoid valves are closed. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 radiates heat in the condenser 3 to be condensed and becomes a gas-liquid mixed refrigerant and flows into the receiver tank 5. In the receiver tank 5, the refrigerant is separated into gas and liquid, and the liquid refrigerant accumulates downward and passes from the outlet side 5A through the outlet side pipe 6 as shown by the solid line arrow in the figure, and the solenoid valve 10
After passing through 11 and 11 and being throttled by the expansion valve 12, the evaporator 1
Flow into 3 The refrigerant flowing into the evaporator 13 is evaporated there, passes through the solenoid valve 14, passes through the low pressure side pipe 15, and flows into the accumulator 16. Here, the non-evaporated liquid refrigerant is separated and only the gas refrigerant is sucked into the compressor 1 through the suction side pipe 26.

The cooling operation is performed for a predetermined time (for example, 3 hours)
After the elapse, the defrosting operation of the evaporator 13 is performed. However, before starting the defrosting operation, a predetermined short period (for example, 30
For a second), the solenoid valve 20 is further opened from the above state, and the refrigerant throttled by the expansion valve 21 is caused to flow into the evaporator 22 as shown by the broken line arrow in the figure to be evaporated. That is, the inside of the showcase is cooled by both the evaporator 13 for the inner layer cool air passage and the evaporator 22 for the outer layer cool air passage. After this cooling operation is completed, the solenoid valve 3
1, 18, 20, 29 and 33 are opened and the other solenoid valves are closed. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the defrosting pipe 30 and the solenoid valves 31, 18 as indicated by the broken line arrow in the figure, and the bypass pipe 17 expands the expansion valve 1
2 is bypassed and flows into the evaporator 13. The evaporator 13 is heated and defrosted by the inflow of the high-pressure gas refrigerant,
At the same time, the refrigerant condensed inside passes through the check valve 25 and the electromagnetic valve 20 from the pipe 24, is throttled by the expansion valve 21, and then flows into the evaporator 22 to be evaporated. This allows the evaporator 13
The interior of the showcase can be cooled by the evaporator 22 even during defrosting. The refrigerant evaporated in the evaporator 22 similarly returns to the accumulator 16. Further, during the defrosting, the high-temperature high-pressure gas refrigerant discharged from the compressor 1 flows into the suction side pipe 15 through the electromagnetic valve 33 and the low-pressure pressure adjusting valve 34, whereby the low-pressure side pressure of the compressor 1 is reduced. Prevents it from falling too low.

The defrosting end temperature of the evaporator 13 is detected by a sensor (not shown), and when the defrosting is finished, only the solenoid valves 20 and 29 should be opened for a predetermined period (for example, 3 minutes), and the other solenoid valves should be closed. Both evaporators 13 and 22
The internal refrigerant recovery operation is performed.

The solenoid valve 29 is open during the above-mentioned respective operation periods. Therefore, the liquid refrigerant accumulated in the receiver tank 5 is squeezed from the liquid injection circuit 27 by the capillary tube 28 and flows into the compressor 1. Evaporates,
Cool the compressor 1.

Next, in the refrigerating apparatus of FIG. 4, the condenser 3 does not exist, and the discharge side pipe 2 connected to the discharge side 1D of the compressor 1 is connected to the receiver tank 5 via the dryer 36.
, Which is connected to the refrigerant inlet side 5A, while the receiver tank 5 has a water-cooling conduit 3 through which cooling water flows.
7 has been introduced. In this case, the refrigerant in the receiver tank 5 is cooled and condensed by the water cooling conduit 37. The flow of water to the water cooling conduit 37 is controlled by the discharge pressure of the compressor 1. When the pressure rises, the water flows, and when it falls, it stops. Other configurations and operations are the same as in the case of FIG.

Next, in the refrigerating apparatus of FIG. 5, the condenser 3
The outlet side pipe 4 is connected to the refrigerant inlet side 5A of the receiver tank 5 via the check valve 39, and the defrosting pipe 30 branches from the outlet side pipe 4 between the condenser 3 and the check valve 39. There is. In addition, the auxiliary accumulator 40 is installed in the low-pressure side pipe 15.
Is interposed. In this case, the condenser 3 is attached to the defrosting pipe 30.
At this time, the gas-liquid mixed refrigerant, which has been subjected to rough heat and condensed, flows in and is used for defrosting the evaporator 13. Other configurations and operations are the same as those in FIG.

[0013]

A predetermined amount of R-22 or R-502 refrigerant is enclosed in the refrigerant circuit of each refrigerating machine, and in any refrigerating machine, the defrosting pipe 30 is the receiver tank. Bypassing 5. Therefore, the amount of refrigerant flowing into the receiver tank 5 during defrosting of the evaporator 13 is small, and particularly in the refrigerating apparatus of FIG. 5, the gas-liquid mixed refrigerant flowing out of the condenser 3 almost flows into the defrosting pipe 30. The liquid refrigerant accumulated in the receiver tank 5 during defrosting drops to 1 to 2 liters.

However, in order to cool the compressor 1, the liquid injection circuit 27 has 600 cc / min.
It is necessary to flow an appropriate amount of liquid refrigerant. Therefore, during defrosting of the evaporator 13, the liquid refrigerant in the receiver tank 5 is depleted at an early stage, so that the liquid refrigerant supplied to the liquid injection circuit 27 is insufficient and the temperature of the compressor 1 rises. If the temperature of the compressor 1 rises, the compressor 1 will be damaged, so that the protective device will work and the compressor 1 will stop.

That is, when the amount of the refrigerant enclosed in the refrigerating apparatus was tested so that the flash gas was generated in the portion of the sight glass 8, the head temperature of the compressor 1 during defrosting in the refrigerating apparatus of FIG. Exceeds + 120 ° C, and the compressor 1 is stopped due to the protection device being activated. When the compressor 1 is stopped in this way, there is a problem that the defrosting of the evaporator 13 is not performed.

In the refrigerating apparatus of FIG. 3 or 4, the high-temperature high-pressure gas refrigerant discharged from the compressor 1 bypasses the receiver tank 5 and flows into the defrosting pipe 30, so that the liquid flowing into the liquid injection circuit 27. Although the compressor 1 was not stopped in the same experiment as described above due to lack of refrigerant, the head temperature of the compressor 1 was still +1.
The temperature became 20 ° C or higher, and the state became extremely unstable.

When defrosting the evaporator with a high-pressure gas refrigerant, there is also a method of using the gas refrigerant after gas-liquid separation in a receiver tank, as in JP-B-49-20022.

In view of the above-mentioned conventional techniques and the problems of the conventional techniques, the present invention achieves stable cooling of the compressor by the liquid injection circuit even when the defrosting of the evaporator is performed by the high pressure gas refrigerant. An object is to provide a refrigeration system capable of

[0019]

A refrigerating apparatus according to a first aspect of the present invention is a compressor 1 having a refrigerant discharge side 1D and a suction side 1S.
And a condenser 3 connected to the discharge side 1D of this compressor 1.
And the condenser 3 connected to the refrigerant outlet side 3B of the condenser 3.
And a receiver tank 5 for separating the refrigerant from the refrigerant into a gas refrigerant and a liquid refrigerant, and a refrigerant outlet side 5B of the receiver tank 5.
13 connected between the suction side 1S of the compressor 1 and the compressor 1
In the refrigerating apparatus having, the defrosting circuit (defrosting pipe) 30 that drives the compressor 1 during defrosting of the evaporator 13 and that supplies the gas refrigerant separated in the receiver tank 5 to the evaporator 13 And a liquid injection circuit 27 that supplies the liquid refrigerant separated into gas and liquid in the receiver tank 5 to the low pressure side inside the compressor 1 when the evaporator 13 is cooled and defrosted.

A refrigerating apparatus according to a second aspect of the present invention is a compressor 1 having a refrigerant discharge side 1D and a suction side 1S, and the compressor 1
Receiver tank 5 that is connected to the discharge side 1D of the condenser 3 and that separates the refrigerant from the condenser 3 into a gas refrigerant and a liquid refrigerant, a water cooling conduit 37 for cooling the receiver tank 5, and a refrigerant outlet side of the receiver tank 5. 5B and suction side 1 of compressor 1
In a refrigerating apparatus having an evaporator 13 connected between S and S, the compressor 1 is operated when the evaporator 13 is defrosted, and a gas refrigerant separated in the receiver tank 5 is supplied to the evaporator 13. A defrosting circuit (piping pipe for defrosting) 30
The liquid refrigerant separated into gas and liquid in the receiver tank 5 is evaporated by the evaporator 1.
3 has a liquid injection circuit 27 that supplies the low-pressure side inside the compressor 1 during cooling and defrosting.

[0021]

In the refrigerating apparatus of the first aspect, all the refrigerant discharged from the compressor 1 and condensed in the condenser 3 once flows into the receiver tank 5. During defrosting of the evaporator 13, the gas refrigerant in the refrigerant separated into gas and liquid in the receiver tank 5 flows into the defrosting pipe 30 and is used for defrosting. On the other hand, the liquid refrigerant separated into gas and liquid in the receiver tank 5 accumulates in the receiver tank 5, and the compressor 1 is operated even when the evaporator 13 is defrosted from the liquid injection circuit 27.
Reserved for cooling.

In the refrigerating apparatus of the second aspect, all the refrigerant discharged from the compressor 1 once flows into the receiver tank 5. When the evaporator 13 is defrosted, the defrosting pipe 30 is supplied with the gas refrigerant, which is the refrigerant that has been condensed by the water cooling pipe 37 in the receiver tank 5 and separated into gas and liquid, and is used for defrosting. On the other hand, the liquid refrigerant separated into gas and liquid in the receiver tank 5 collects in the receiver tank 5 and is secured for cooling the compressor 1 operating from the liquid injection circuit 27 even when the evaporator 13 is defrosted. To be done.

[0023]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a refrigerant circuit of a refrigerating apparatus as an embodiment of the invention of claim 1, and FIG. 2 shows a refrigerant circuit of a refrigerating apparatus as an embodiment of the invention of claim 2. In FIG. 1, the same reference numerals as those in FIG. 3 denote the same elements, and the same reference numerals as those in FIG. 4 denote the same elements in FIG.

The difference between FIG. 1 and FIG. 3 is that the defrosting pipe 30 and the pipe 32 are branched from the discharge side pipe 2 in FIG. 3, whereas in the invention of FIG. No branch pipe is connected to the outlet side pipe 4, a gas refrigerant outlet 5C is newly formed above the receiver tank 5, and the defrosting pipe 30 and the pipe 32 are connected to the pipe 41 connected to the gas refrigerant outlet 5C. Is what you are doing. Other configurations and the respective operation operations of the cooling by the evaporator 13, the cooling by both the evaporators 13 and 22, the defrosting of the evaporator 13 and the refrigerant recovery are the same as those in FIG.

The difference between FIG. 2 and FIG. 4 is that the defrosting pipe 30 and the pipe 32 are branched from the discharge side pipe 2 in FIG. 4, whereas in the invention of FIG. Is not connected to any branch pipe, a gas refrigerant outlet 5C is newly formed in the upper portion of the receiver tank 5 as in FIG. 1, and the pipe 41 connected to this gas refrigerant outlet 5C is connected to the defrosting pipe 30 and the pipe 32.
Is connected. The other configurations and the above-mentioned respective driving operations are the same as those in FIG.

In the refrigerating apparatus of FIG. 1, the compressor 1 is operated even during defrosting of the evaporator 13 in which the solenoid valves 31 and 33 are open.
The high-temperature and high-pressure gas refrigerant discharged from the condenser 3 is condensed in the condenser 3 and then once flows into the receiver tank 5. The liquid refrigerant in the refrigerant flowing into the receiver tank 5 accumulates in the lower part, and the gas refrigerant separates in the upper part. The gas refrigerant having a relatively low temperature in the receiver tank 5 flows into the defrosting pipe 30 and is used for defrosting the evaporator 13. Further, this gas refrigerant flows into the low-pressure side pipe 15 from the pipe 32 to prevent the low-pressure side pressure of the compressor 1 from dropping too much during defrosting, but since the temperature is lower than that of the high temperature gas in FIG. It is possible to prevent the suction side temperature of the machine 1 from increasing. Further, the pipe 32
There is also an effect that the defrosting circuit can be integrated together with the defrosting pipe 30 by connecting to the pipe 41.

By using the gas refrigerant separated in the receiver tank 5 as the refrigerant for defrosting the evaporator 13 in this way, all the refrigerant discharged from the compressor 1 flows into the condenser 3, Therefore, all the condensed liquid refrigerant is secured in the receiver tank 5. Therefore, during defrosting of the evaporator 13, even if the liquid refrigerant in the receiver tank 5 flows into the liquid injection circuit 27 from the refrigerant outlet side 5B to cool the compressor 1 (at this time, the solenoid valve 10 is closed). However, the liquid refrigerant in the receiver tank 5 is not exhausted, and the cooling of the compressor 1 can be reliably achieved.

Also in the refrigerating apparatus of FIG. 2, all the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 once flows into the receiver tank 5 during defrosting of the evaporator 13 in which the solenoid valves 31 and 33 are open. The refrigerant that has flowed into the receiver tank 5 is condensed by the cooling from the water cooling pipe line 37, the liquid refrigerant therein is accumulated in the lower portion, and the gas refrigerant is separated into the upper portion. The gas refrigerant having a relatively low temperature in the receiver tank 5 flows into the defrosting pipe 30 and is used for defrosting the evaporator 13. Further, the low pressure side pressure of the compressor 1 is prevented from dropping too much during defrosting by flowing from the pipe 32 into the low pressure side pipe 15, but similarly, this gas refrigerant has a lower temperature than the high temperature gas in FIG. Therefore, the suction side temperature of the compressor 1 can be prevented from increasing. Further, similarly, by connecting the pipe 32 to the pipe 41, there is also an effect that the defrosting circuit can be integrated together with the defrosting pipe 30.

Further, as in the case of FIG. 1, since the gas refrigerant which has been gas-liquid separated in the receiver tank 5 is used as the defrosting refrigerant for the evaporator 13, all the refrigerant discharged from the compressor 1 is received by the receiver tank 5. All the liquid refrigerant that has flowed into and is condensed therein is secured in the receiver tank 5. Therefore, during defrosting of the evaporator 13, even if the liquid refrigerant in the receiver tank 5 flows into the liquid injection circuit 27 from the refrigerant outlet side 5B and is used for cooling the compressor 1 (at this time,
(The electromagnetic valve 10 is closed), the liquid refrigerant in the receiver tank 5 is not exhausted, and cooling of the compressor 1 can be reliably achieved.

That is, even when the amount of the refrigerant filled in the refrigerating apparatus is tested so that the flash gas is generated in the portion of the sight glass 8 (the refrigerant is also R-22 or R-502), FIG. Alternatively, in the refrigerating apparatus of FIG. 2, the head temperature of the compressor 1 during defrosting is about + 116 ° C., and the compressor 1 does not stop due to the protection device working.
The temperature was also stable.

Although the present invention is applied to the freezing / refrigerating showcase having the evaporator for the inner-layer cold air passage and the evaporator for the outer-layer cold air passage in the embodiment, the present invention is not limited to this, and cooling of a freezer / refrigerator or a prefabricated refrigerator is also possible. The present invention is also effective for units and the like. Further, it is not limited to the type of refrigerant or compressor used.

[0032]

As described above, according to the present invention, the gas refrigerant in the refrigerant separated in the receiver tank is used as the refrigerant for defrosting the evaporator, and the liquid separated in the receiver tank is used. Refrigerant is reserved in the receiver tank for cooling the compressor by the liquid injection circuit, so the liquid refrigerant to the liquid injection circuit for cooling the operating compressor is exhausted even when the evaporator is defrosted. Without this, stable cooling of the compressor can be realized, and defrosting of the evaporator can be surely achieved.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigerating apparatus according to a first aspect of the invention.

FIG. 2 is a refrigerant circuit diagram of the refrigerating apparatus of the invention of claim 2.

FIG. 3 is a refrigerant circuit diagram of a conventional refrigeration system of a type in which a refrigerant is condensed by air cooling and a high-pressure gas refrigerant discharged from a compressor is directly flown to an evaporator during defrosting.

FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration system of a type in which a refrigerant is condensed by water cooling and a high-pressure gas refrigerant discharged from a compressor is directly flown to an evaporator during defrosting.

FIG. 5 is a refrigerant circuit diagram of a conventional refrigeration system of a type in which a refrigerant is condensed by air cooling and a gas-liquid mixed refrigerant discharged from a condenser at the time of defrosting is caused to flow to an evaporator.

[Explanation of symbols]

 1 Compressor 3 Condenser 5 Receiver Tank 13 Evaporator 27 Liquid Injection Circuit 30 Defrosting Pipe 37 Water Cooling Pipeline

Claims (2)

(57) [Claims] 1. A compressor having a refrigerant discharge side and a suction side, a condenser connected to the discharge side of the compressor, and a refrigerant discharged from the condenser connected to a refrigerant outlet side of the condenser. cold
In a refrigerating apparatus having a receiver tank for separating a medium and a liquid refrigerant, and an evaporator connected between a refrigerant outlet side of the receiver tank and a suction side of the compressor ,
While defrosting the generator, the compressor is operated and
The gas refrigerant separated into gas and liquid in the sea bar tank is added to the evaporator.
Defrosting circuit to supply the gas and liquid in the receiver tank.
When the separated liquid refrigerant is cooled in the evaporator and defrosted,
Liquid injection that supplies to the low pressure side inside the compressor
And a refrigeration device having a circuit . 2. A compressor having a refrigerant discharge side and a suction side, and a refrigerant from the condenser connected to the discharge side of the compressor.
A receiver tank for separating the gas refrigerant and the liquid refrigerant ,
In a refrigerating apparatus having a water cooling pipeline for cooling the receiver tank, and an evaporator connected between a refrigerant outlet side of the receiver tank and a suction side of the compressor ,
While operating the compressor when defrosting the evaporator,
The gas refrigerant separated into gas and liquid in the receiver tank is
Defrost circuit to supply to the evaporator and inside the receiver tank
The liquid refrigerant that has been separated into gas and liquid at the time of cooling and defrosting the evaporator
Liquid injection to be supplied to the low pressure side inside the compressor
And a refrigeration device having an application circuit.